When they were boys, Alex Horne and Owen Powell obsessively collected Panini football stickers. Now the two friends have embarked on a more daunting task: instead of hunting down that elusive Portuguese striker, they are trying to find a person from every country in the world who lives in London.

Their quest for the 'World in One City' was launched on 24 October last year, United Nations Day. More than seven months later, they have ticked off more than half of the UN's 192 official nationalities, starting with the Philippines and leading in the last week alone to Albania, Finland, Uganda, Vietnam and Senegal, the 112th profile added to their blog, worldinonecity.blogspot.com. The 2001 census said the capital contained people who said they were from a total of 243 countries. The pair, who perform separately as comedians, began their quest at Charing Cross - the official epicentre of the capital, from which all distances to and from London are measured - plucking up the courage to approach their first 'foreigner', Carl from the Philippines, who was guarding a motion simulator attraction in the Trocadero centre in Piccadilly.

Since then they have accosted road-sweepers, an emergency plumber, a work colleague, neighbours, waiters and, as the project has mushroomed, friends of candidates already signed up.

One chain of people took them from Ligia, a Colombian, to her colleague from Bulgaria, to her housemate from Mexico, to a percussionist from Spain whom Owen interviewed while they watched their football teams (Seville and Tottenham Hotspur) playing each other in the Uefa Cup.

Most of the people are in their twenties and thirties, which Powell thinks is because so many people in London are young. He and Horne are both 28.

An unscientific survey of the profiles involved suggests that most people who have come to London want to stay. Many like the capital's buzz and feeling of tolerance, and there are even votes for the weather and the food.

However, most find London a hard place to make English friends and miss their friends and families and home cooking.

Some have fled violence, whether domestic or warfare. Others left middle-class families with servants to further their careers. Some arrived at railway stations with no home, no money and almost no English; others were transferred by employers to work in the City. Some left children behind; others came to be with lovers.

Now their jobs include waiter and cafe owner, butler and banker, designers, an architect, teachers, people who hand out free newspapers, artists and musicians, office workers and a property manager for the International Society for Krishna Consciousness.

Their stories are punctuated by the two friends' factual data. Visitors to their website learn that Singapore is the second most densely populated country in the world, or that more Cape Verdeans live outside their country than in it. Other asides are more philosophical, as they discuss what they are learning about the project, immigration, politics and detail about the lives that most Londoners will never delve into.

'We went into the project thinking it was going to be very light-hearted and fun,' said Horne. 'Some of the things are fun, but some are pretty harrowing. The Kyrgyzstani lady I met two days ago came to escape a husband who was beating her up. She reckons 80 per cent of women in Kyrgyzstan are beaten regularly by their husbands. It's the sort of country you never really read about. Each story is different, some will be sad, some will be happy.'

Along the way, Horne and Powell, who met at Cambridge University, have also learnt a lot about London, from its architecture to where to get good Ghanaian food and about ethical tensions between English people and recent immigrants, or between different ethnic groups. Many Afro-Caribbeans, for example, resent the influx of eastern Europeans, Horne said. 'They feel quite loyal to being a part of British history, but they don't feel loyalty to the European Union.'

The website where their 'collection' is being logged lists the nationalities in the order they are found, generating a quirky and perhaps democratic view of the world.

The Philippines, Poland and Bangladesh sit on top and the Netherlands is sandwiched between Nigeria and Ireland, with Greece falling between Indonesia and Zimbabwe.

Horne and Powell both have solo shows at the Edinburgh Fringe Festival next month and hope to stage a one-off show about their project. They have hopes of a book deal, and would like to get everybody into one room for a worldwide party.

Nigeria

Benjy, 48 Security guard, Globe Theatre; lives in Croydon

Benjy arrived in London 20 years ago to study journalism in London and Portsmouth. He has been working at the Globe, a precise reconstruction of Shakespeare's own performance space, for five years. He is the first person most visitors meet and is one of the few people who knows all the staff by name. He recommends a restaurant called Safaris in Streatham.

Colombia

Ligia, 31 Magazine designer; lives in Sydenham

Ligia trained in the Colombian capital, Bogota, for nine years, but left for London to develop her career and because she thought Colombian men were too macho. She is now married to a man from Northern Ireland. She landed her first design job in London with the Voice newspaper after offering to work for free. She still misses dancing in Colombia: 'If you can't dance, what do you do at parties?'

Georgia

Berdia, 32 IT manager; lives near Tower Bridge

Berdia was at university in the Georgian capital, Tbilisi, during the 1991-92 civil war. He left two sons to come to London three years ago. 'For six months I lived on five hours' sleep a day,' he recalls. 'You can do anything here if you're hard working.' He wants to bring his sons over, after schooling in Georgia: 'A person has to know his own country before he can travel the world, otherwise he's lost.'

Dominican Republic

Paola, 28 Works for Siemens; lives Bermondsey

Paola first tasted British life when she did a masters degree at Birmingham University in 2002, returning to London last year on the highly skilled migrant programme. She likes England's colder weather, but she misses home food. 'I still can't understand how some people eat cold sandwiches and crisps for lunch,' she says. 'It's the most important main meal of the day - it should at least be hot.'